Remote sensing of water leaks from rural aqueducts

The development of techniques for the detection of water leaks from underground pipelines is seen as a high profile activity by water companies and regulators. This is due to increasing water demands and problems with current leak detection methods. In this thesis optical reflectance and microwave backscatter were used to identify optimal indices for detecting water leaks amongst a variety of different land cover types at different growth stages. Ground-based surveys and modelling techniques were used to establish optimal wavelengths for detection. Results from these studies suggested that in the optical domain visible/middle infrared ratios show potential for leak detection for a wide range of leak types, under a variety of vegetation canopies at different growth stages. Given the sensitivity of L-band radar to moisture, and the ability to separate contributions from canopy and ground surface, it is possible to detect surface water beneath a range of vegetation canopies. The optimal leak detection indices were then used to idenitfy leaks on airborne image data. The available image data was L - band fully polarimetric E-SAR data, and 126 channel HYMAP hyperspectral airborne data which were acquired over an 8km section of the Vrynwy aqueduct (UK), which included a high concentration of leaks. Four of the five leaks were identifiable on the optical image data and none of the leaks were detectable on the microwave data. However the E-SAR data was obtained under unfavourable conditions. The results of both approaches are used to infer limits of detection in terms of season and meteorological conditions for a range of land covers. Preliminary findings suggest that leaks may be optimally detected when canopy height is low, surrounding soil is dry after a period of no rain, and the leak has been present for at least 2 days. The results from this work suggest that remote sensing is both an effective and feasible tool for leak identification

High Redshift Galaxies As Probes Of The Epoch Of Reionization

Following the Big Bang, as the Universe cooled, hydrogen and helium recombined, forming neutral gas. Currently, this gas largely resides between galaxies in a highly diffuse state known as the intergalactic medium (IGM). Observations indicate that the IGM, fueled by early galaxies and/or accreting black holes, ``reionized\u27\u27 early in cosmic history--the entire volume of the Universe refilling with ionized gas. This thesis analyzes and develops several ways to use observations of high redshift galaxies to probe this period, the Epoch of Reionization (EoR). We examine the redshift evolution of the Ly-alpha fraction, the percentage of Lyman-break selected galaxies (LBGs) that are Lyman-alpha emitting galaxies (LAEs). Observing a sharp drop in this fraction at z ~ 7, many early studies surmised the z ~ 7 IGM must be surprisingly neutral. We model the effect of patchy reionization on Ly-alpha fraction observations, concluding that sample variance reduces the neutral fraction required. We quantify the prospects for measuring the enhanced spatial clustering of LAEs due to reionization with upcoming observations from the Hyper Suprime Cam. LBGs from that survey provide a useful comparison sample. We consider the effect of foreground ``interlopers\u27\u27 on the clustering signal. We conclude that if HSC observes back into the EoR, the abundance and spatial clustering of galaxies and the size distribution of void regions evolve more strongly with redshift for LAEs than LBGs. Moreover, measuring the cross-power spectrum between LAEs and LBGs reduces the interloper effect. We examine line intensity mapping experiments which trace large scale structure by measuring spatial fluctuations in the combined emission, in some convenient spectral line, from individually unresolved galaxies. We develop a technique to separate ``interloper\u27\u27 emissions, which these surveys are vulnerable to, at the power spectrum level, based on distortions introduced when the interloper emissions are (incorrectly) assumed to originate from the target redshift. Applying this to a hypothetical [CII] emission survey at z ~ 7, we find the distinctive interloper anisotropy can be used to separate strong foreground CO emission fluctuations

Coworking: Crafting Lives Alongside Each Other

Coworking is a form of alternative work arrangement in which communities of individuals share common office and work space but are most often employed by different employers within different fields/industries (Foertsch, 2011). Despite its growing prevalence, coworking is nearly absent from the organizational literature. The present mixed methods study introduced and defined the construct of extent of coworking. Extent of coworking is conceptually defined in this research as the degree to which an individual spends her/his workweek coworking. Qualitative literature review was conducted to establish this construct, and qualitative interview data provided support for the definition. Using job crafting and conservation of resources theory, the present study also investigated how extent of coworking related to employees’ personal and professional outcomes of work-family conflict, job satisfaction, life satisfaction, and job performance. Minimal support was found for the links connecting extent of coworking to the outcomes of interest, suggesting possible measurement issues. Job crafting was not shown to moderate any of the proposed relationships. This research extends the application of a quantitative measure of job crafting to the US and provides a foundation for better understanding coworking within the organizational literature

Interrupting prolonged sitting with intermittent physical activity in adults with abnormal glucose metabolism : Effects on vascular function

Sedentary behaviours, defined as waking behaviours undertaken in a sitting/lying posture with low energy expenditure (i.e., ≤ 1.5 metabolic equivalent of tasks [METS]), are now recognised as being strongly associated with all-cause and cardiovascular disease (CVD)-related mortality. Specifically, acute experimental studies have reported prolonged uninterrupted sitting to exacerbate postprandial cardiometabolic risk biomarkers [1] and decrease vasodilatory function [2-4] People with abnormal glucose metabolism (which refers to a combination of clinical disorders that increase the risk for diabetes and cardiovascular disease) are disproportionally affected by the risks associated with prolonged uninterrupted sitting, owing partly to vascular dysfunction and consequent predisposition to atherosclerosis. Lifestyle modification remains a cornerstone treatment for the prevention and management of CVD, and recent World Health Organization (WHO) guidelines have been expanded to include a recommendation to reduce and regularly replace sedentary time (sedentary behaviour) with activity. Despite this, relatively little is known about the effects of prolonged sitting on vascular function in those with abnormal glucose metabolism. Additionally, it is currently unknown whether reducing and interrupting sitting time with activity positively influences vascular function in these population groups. The primary aim of this Thesis was to examine the extent and nature of vascular impairment in response to prolonged sitting across the abnormal glucose spectrum; with a focus on reducing and interrupting time spent sitting with activity in clinical populations. Study 1 aimed to determine the dose-response relationship between acute prolonged uninterrupted sitting and vascular function through a systematic review and meta-analysis. Additional sub-group analyses examined the effect of prolonged sitting in healthy adults relative to those with abnormal glucose metabolism. A secondary aim was to compare the acute effects of uninterrupted prolonged sitting to interventions involving acute light activity interruptions. The findings revealed that lower-limb vascular function is progressively impaired as time spent in prolonged sitting increases. Moreover, it was observed that prolonged sitting decreased lower-limb vascular function in healthy adults, who had higher a priori vascular function, but not in those with metabolic and vascular dysfunction. However, the limited number of studies in those with abnormal glucose metabolism make it difficult to draw conclusive findings. Additionally, while interrupting sitting with brief bouts of physical activity improved vascular function, considerable heterogeneity was reported between trials, likely due to differing experimental design (mode, frequency, and duration of breaks). Study 2 compared the acute effects of interrupting sitting with two different activity protocols of equivalent activity duration on vascular function in a clinical population with abnormal glucose metabolism - those with type two diabetes (T2D). Femoral flow-mediated dilation (FMD) averaged across 7h significantly increased when prolonged sitting was interrupted with 3 min of SRAs every 30 min. However, relative to prolonged sitting, interrupting sitting every 60 min with 6 min simple resistance activities (SRAs) did not result in significant changes in vascular function. Vascular shear rate and blood flow were also enhanced by interrupting sitting with SRAs, regardless of frequency. These findings suggest that more frequent, shorter interruptions may be more beneficial than longer, less frequent breaks for vascular improvement in those with T2D. Further, the study provides new insights into the frequency and duration of activity breaks that may be required to improve vascular function during prolonged sitting. In addition to identifying a lack of studies assessing vascular function and sedentary behaviour in populations with metabolic dysfunction, study 2 also reported a lack of female participants in the trials conducted to date. Study 3 sought to address this gap by examining the effect of prolonged uninterrupted sitting on femoral vascular function in young women with polycystic ovary syndrome (PCOS). Relative to 3.5h prolonged sitting, interrupting sitting with 3 min of SRAs every 30 min significantly increased mean femoral resting shear and blood flow. However, no change was observed in FMD between conditions. Collectively, this Thesis has contributed new knowledge to the sedentary behaviour and vascular function research field, specifically: by 1) highlighting the progressive impairment of lower-limb vascular function in response to prolonged uninterrupted sitting; 2) demonstrating that interrupting prolonged sitting with more frequent and shorter activity breaks may be more beneficial than longer, less frequent breaks, for vascular health, in those with T2D, and 3) demonstrating that interrupting prolonged sitting with activity breaks improves blood flow and shear rate for women with PCOS. Future research could build on these findings to focus on three key areas: 1. Obtaining a greater understanding of how vascular function changes over time in response to prolonged sitting. This includes free-living and longer-term studies, in addition to acute studies that measure vascular function at multiple time points across the day. 2. Assessing varying modes, duration, and frequency of interruptions in prolonged sitting to identify optimum activity interruptions. 3. Inclusion of female participants and older and clinical populations into clinical trials to enhance the generalisability of public health recommendations

The effect of perceived spatial distance on the decision to relocate for graduate education

This study investigated the influence of perceived spatial distance (PSD) on students’ intentions and decisions to relocate to pursue graduate education. The framework of the theory of planned behavior (TPB) provided the basis for measurement of the components of PSD, that is one’s attitude, subjective norm, and perceived behavioral control about spatial distance, as well as an understanding of how PSD may influence relocation intentions and decisions. The components of PSD were hypothesized to be positively related to relocation decisions, with relocation intentions acting as a moderator. Undergraduate students at Louisiana State University who had applied to at least one academic or professional graduate program and intended to graduate within one calendar year of beginning the survey served as the sample. They completed a web-based survey assessing the PSD components and intentions to relocate for postgraduate education at Time 1. Three months later at Time 2, these predictors were reassessed to establish construct stability, and for participants to report their ultimate relocation decisions. Correlation, regression, and relative importance analysis were used to test the hypothesized relationships. Overall, this exploration into PSD suggests that the constructs of PSD are stable over time, and that the components of PSD, especially subjective norms, are predictive of behavioral relocation intentions and decisions